-stable review patch. If anyone has any objections, please let us know. ------------------ From: James Chapman changeset 91781004b9c029ee55b7aa9ef950a373ba865dc6 in mainline. [PPP]: L2TP: Fix oops in transmit and receive paths Changes made on 18-sep to fix skb handling in the pppol2tp driver broke the transmit and receive paths. Users are only running into this now because distros are now using 2.6.23 and I must have messed up when I tested the change. For receive, we now do our own calculation of how much to pull from the skb (variable length L2TP header) rather than using skb_transport_offset(). Also, if the skb isn't a data packet, it must be passed back to UDP with skb->data pointing to the UDP header. For transmit, make sure skb->sk is set up because ip_queue_xmit() needs it. Signed-off-by: James Chapman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/pppol2tp.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) --- a/drivers/net/pppol2tp.c +++ b/drivers/net/pppol2tp.c @@ -487,7 +487,7 @@ static int pppol2tp_recv_core(struct soc { struct pppol2tp_session *session = NULL; struct pppol2tp_tunnel *tunnel; - unsigned char *ptr; + unsigned char *ptr, *optr; u16 hdrflags; u16 tunnel_id, session_id; int length; @@ -495,7 +495,7 @@ static int pppol2tp_recv_core(struct soc tunnel = pppol2tp_sock_to_tunnel(sock); if (tunnel == NULL) - goto error; + goto no_tunnel; /* UDP always verifies the packet length. */ __skb_pull(skb, sizeof(struct udphdr)); @@ -508,7 +508,7 @@ static int pppol2tp_recv_core(struct soc } /* Point to L2TP header */ - ptr = skb->data; + optr = ptr = skb->data; /* Get L2TP header flags */ hdrflags = ntohs(*(__be16*)ptr); @@ -636,12 +636,14 @@ static int pppol2tp_recv_core(struct soc /* If offset bit set, skip it. */ if (hdrflags & L2TP_HDRFLAG_O) { offset = ntohs(*(__be16 *)ptr); - skb->transport_header += 2 + offset; - if (!pskb_may_pull(skb, skb_transport_offset(skb) + 2)) - goto discard; + ptr += 2 + offset; } - __skb_pull(skb, skb_transport_offset(skb)); + offset = ptr - optr; + if (!pskb_may_pull(skb, offset)) + goto discard; + + __skb_pull(skb, offset); /* Skip PPP header, if present. In testing, Microsoft L2TP clients * don't send the PPP header (PPP header compression enabled), but @@ -651,6 +653,9 @@ static int pppol2tp_recv_core(struct soc * Note that skb->data[] isn't dereferenced from a u16 ptr here since * the field may be unaligned. */ + if (!pskb_may_pull(skb, 2)) + goto discard; + if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03)) skb_pull(skb, 2); @@ -708,6 +713,10 @@ discard: return 0; error: + /* Put UDP header back */ + __skb_push(skb, sizeof(struct udphdr)); + +no_tunnel: return 1; } @@ -1049,6 +1058,8 @@ static int pppol2tp_xmit(struct ppp_chan /* Get routing info from the tunnel socket */ dst_release(skb->dst); skb->dst = sk_dst_get(sk_tun); + skb_orphan(skb); + skb->sk = sk_tun; /* Queue the packet to IP for output */ len = skb->len; -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/